Defrost: This allows the microwave to run on a lesser power. This is perfect to use when trying to soften cream cheese or butter.
Convection: This means that there is a fan blowing the hot air, evenly heating up the interior, which allows the food to cook much faster than in a conventional oven.
Combination: This is the combination of both microwave mode and convection mode...food will cook faster and will brown.
Thank you, Weight Watchers!